KILNS & FURNACES
Electric in air to 1800°C • Research • Heat treatment
Controlled atmosphere • Melting • Gas, Natural/LPG to 2300°C
Tetlow Kiln Pty. Ltd. ABN: 26 166 832 300 54 Howleys Road, Notting Hill, 3168 Victoria Australia
T: +61 3 8545 8296 F: +61 3 9544 2723 E: info@tetlow.com.au www.tetlow.com.au
SECTION 8 - KILN BUNG GUIDELINES
For pottery and ceramics we’d suggest you leave your bung(s) out till the kiln has reached around
250°C - 300°C. This will allow any excess moisture and clay gases from the ware to escape the
chamber. Above this temperature, the bung(s) should ideally be placed in the bung-holes. This
will ensure that the heat loss is minimised. Operating with the bungs out at higher temperature
can, in some cases, prevent the kiln from achieving maximum operating temperature.
If you can’t be there to put them back in at the above recommended temperature, you can leave
just one of the bungs out in the top, this will allow for most of the gasses to leave the kiln.
Operating with the bungs out for the entire cycle is not generally recommended. Once the kiln
achieves a higher temperature the heat loss from the bung holes is quite significant and can, in
some cases, prevent the kiln from achieving maximum operating temperature and can, over time,
result in damage to the kiln elements and/or insulation due to excessive time at the higher
temperatures (over-firing).
Conversely, if the bungs are left in the kiln all the time (i.e. not removed at the start of firing),
damage to the kiln elements and/or insulation can occur due to excess moisture and clay gases
which are unable to discharge from the kiln.
For ‘Glass’ or Glaze firing the bungs should generally be left in unless you are using moulds that
contain moisture. If you have lost or broken bungs please contact Tetlow Kilns & Furnaces for a
replacement. For reasons noted above, it is not recommended to fire a kiln without using bung(s).
SECTION 9 – KILN LOADING GUIDELINES
It is normal practice to maximize the amount of pottery loaded into the kiln, whilst having regard to
the clearances, and other characteristics required for good operation of the kiln. Typically, pottery
ware is loaded on multiple levels separated by kiln shelves or batts (made from cordierite or other
kiln-safe material) and props of varying heights. Choose pieces to load based on height, and other
relevant characteristics. It is common practice to load tall pieces on one level, and shorter pieces
on another. If the kiln load has items of different sizes, consider splitting the shelves to maximize
space. Always try to load the kiln evenly, from side to side, top to bottom. This will help ensure the
kiln provides an even firing. The kiln applies the same heat pattern regardless of the load, so
always try to "keep things symmetrical".
Generally, support each shelf with three posts instead of four. Four posts can cause the shelves to
wobble unless the bottom of the kiln is even, the shelves are flat, and the posts are exactly the
same height. You can still use four if you wish, just make sure the shelves are as stable as
possible.
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